Charles algernon parsons



J C. A, PARSONS. GEARED TURBINE INSTALLATIONFOR SHIP PROPULSION.

v APPLICATIQN FILEQ OCT. 23. I916 1 02,962, Patented May 6,1919.

Inventor:

Charles 11% rnonBzr-Jmg A a r CHARLES ALGERNON PARSONS, OF NEWCASTLE-UPON-TYNE, ENGLAND.

GEARED-TURBINE INSTALLATION FOR SHIP PROPULSION.

Application filed October 23, 1916, Serial No. 127,304.

To all whom it may concern:

Be it known that I, CHARLES ALGERNON PARSONS, a subject of the King of Great Britain and Ireland, residing at Heaton Works, Newcastle-upon-Tyne, in the county of Northumberland, England, have invented certain new and useful Improvements in and Relating to Geared-Turbine Installations for Ship Propulsion, of which the following is a specification.

The present 1nvent1on relates to a marine propulsion system of differently sp'eeded turbines driving a common shaft in which two or more turbines are geared to the propeller shaft through double reduction gearing, such, for example, as are described in the British patent specification No. 25651 of 1909.

It is well known that the reaction type of blading is in itself more eflicient than any other type, but its high efficiency is in practice to a certain extent encroached upon by reason of the losses which occur through the peckingof the balancing piston and through figs clearance spaces of the tips of the blades,

ese losses being most serious in the high pressure stages.

The first mentioned loss may be obviated by constructing the turbine in the manner described in the British specification No. 953 of 1913 in which the balancing pistons are dispensed with and the axial thrust upon the rotor is taken by a pivoted thrust bear- 111g".

The second mentioned loss may be considerably reduced by fitting projecting shrouds to the blades and controlling the clearance of axial adjustment as described in the British patent specification No. 12347 of 1901 and this loss can be further reduced by making the turbine of small diameter with long blades, the reduction in diameter being accompanied by a corresponding increase in the rate of revolution so as to maintain a high blade velocity corresponding to maximum efiiciency.

In order to obtain the maximum .blade I 5 height practically possible for each stage, all

the stages may be sub-divided into separate units with separate pimons corresponding to difierentspeeds, and proposals have been made for installations of thev type to arge number of geared turbines are employed, as is the case in the British patent specification No. 25651 of 1909. The gainso obtained,

Specification of Letters Patent.

Patented May 6, 1919.

The invention consists in -a geared turbine installation for ship propulsion of the type indicated comprising three turbines connected in series for steam flow and operating the propeller shaft through double reduction blading of the reaction type and being constructed without balancing pistons, the high gearing, all the turbines being provided with and intermediate pressure turbine pinions I bein arranged to .operate a common gear whee wh1le the low pressure turbine p1n1on operates another gear wheel, each of these gear wheels operating separate co-axial' pinions engaging with a main gear wheel mounted on the propeller shaft, the high pressure turbine having the highest rate of revolution and thelow pressure turbine having the lowest rate of revolution, while the high and intermediate pressure turbines each develop substantially one quarter of the A total power.

The invention further consists in such an installation in which the high pressure turbine and preferably also the intermediate pressure turbine, are provided with endtightening shrouds of the type described m the British patent specification No. 12347 of The invention'also consists in an installation as abovedescribed in WhICh the h1gh pressure turbine is specially designed to withstand the high temperatures resulting from the employment of superheated steam.

Referring to the accompanying drawin ?igure 1 is an end view of an installation according to the invention, while Fig. 2 is a plan of the same. I

In the installation illustrated the high pressure turbine at and the intermediate turbine 6 drive pinions which are geared to a common gear wheel in the casing 0 driving the pinions d. The low' pressure turbine e drives a gear wheel in the casing f on the I shaft carrying the pinion g. The pinions d and 9 drive the common gear wheel h mounted on the ropeller sha The steam flow is through t e turbines a, b and a in se- Theturbines a, b' and e are fitted with of 1901. Each of the turbines a and 1) provide substantially a quarter of the power 'while the turbine 6 provides one-half the power.

In the section of the turbine shown in Fig. 2 the blades 1 of the rotor are provided with entightening shrouds 2 and the blades 3 of the stator wlth entightening shrouds 4:.

Considerable advantage is obtained by an installation such as above described. Owing to the high rate of revolution of the turbines obtained by the use of double reduction gearing, the turbines are of small diameter and length, and the weight and cost are therefore small. Consequently the blade clearance losses and the rotor thrust to be carried are also small.

The closest approximation to the maximum practically possible blade height relative to the diameter of the turbine is obtained throughout all thestages, while only a small number of separate units is employed.

In cases in which superheated steam is employed the superheat 1s confined to the high pressure turbine a which on account of 1ts small dimensions would have a simple and compact casing not liable. to distortion, while the differential expansions which take place at the high temperatures would be so small as not to effect the endwise control of the clearances by the adjusting block.

Having now fully described and ascertained my said invention, and the'manncr in which it is to be performed, I declare that what I claim is ,Wheels, pinions on said intermediate shafts,

gear wheels on the propeller shaft, said intermediate shaft pinions engaging with said propeller shaft gear wheels, the pinion on said high pressure turbine -shaft being of smaller diameter than the pinion on said intermediate turbine shaft and the pinion on said-intermediate pressure turbine shaft being smaller than the pinion on said low pressure turbine shaft, said high pressureturbine and said intermediate ressure turbine each developing substantia 1y one quarter of the total power, as set forth.

In testimony whereof, I have aflixed my signature.

CHARLES ALGERNON PARSONS. 

